bison/src/print_graph.c

/* Output a graph of the generated parser, for Bison.

   Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010
   Free Software Foundation, Inc.

   This file is part of Bison, the GNU Compiler Compiler.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include <config.h>
#include "system.h"

#include <quotearg.h>

#include "LR0.h"
#include "closure.h"
#include "complain.h"
#include "conflicts.h"
#include "files.h"
#include "getargs.h"
#include "gram.h"
#include "graphviz.h"
#include "lalr.h"
#include "print_graph.h"
#include "reader.h"
#include "state.h"
#include "symtab.h"


/*----------------------------.
| Construct the node labels.  |
`----------------------------*/

static void
print_core (struct obstack *oout, state *s)
{
  size_t i;
  item_number *sitems = s->items;
  size_t snritems = s->nitems;

  /* Output all the items of a state, not only its kernel.  */
  if (report_flag & report_itemsets)
    {
      closure (sitems, snritems);
      sitems = itemset;
      snritems = nitemset;
    }

  obstack_fgrow1 (oout, "%d", s->number);
  for (i = 0; i < snritems; i++)
    {
      item_number *sp;
      item_number *sp1;
      rule_number r;

      sp1 = sp = ritem + sitems[i];

      while (*sp >= 0)
	sp++;

      r = item_number_as_rule_number (*sp);

      obstack_fgrow1 (oout, "\n%s -> ", rules[r].lhs->tag);

      for (sp = rules[r].rhs; sp < sp1; sp++)
	obstack_fgrow1 (oout, "%s ", symbols[*sp]->tag);

      obstack_1grow (oout, '.');

      for (/* Nothing */; *sp >= 0; ++sp)
	obstack_fgrow1 (oout, " %s", symbols[*sp]->tag);

      /* Experimental feature: display the lookahead tokens. */
      if (report_flag & report_lookahead_tokens
          && item_number_is_rule_number (*sp1))
	{
	  /* Find the reduction we are handling.  */
	  reductions *reds = s->reductions;
	  int redno = state_reduction_find (s, &rules[r]);

	  /* Print them if there are.  */
	  if (reds->lookahead_tokens && redno != -1)
	    {
	      bitset_iterator biter;
	      int k;
	      char const *sep = "";
	      obstack_sgrow (oout, "[");
	      BITSET_FOR_EACH (biter, reds->lookahead_tokens[redno], k, 0)
		{
		  obstack_fgrow2 (oout, "%s%s", sep, symbols[k]->tag);
		  sep = ", ";
		}
	      obstack_sgrow (oout, "]");
	    }
	}
    }
}


/*---------------------------------------------------------------.
| Output in graph_obstack edges specifications in incidence with |
| current node.                                                  |
`---------------------------------------------------------------*/

static void
print_actions (state const *s, FILE *fgraph)
{
  int i;

  transitions const *trans = s->transitions;

  if (!trans->num && !s->reductions)
    return;

  for (i = 0; i < trans->num; i++)
    if (!TRANSITION_IS_DISABLED (trans, i))
      {
	state *s1 = trans->states[i];
	symbol_number sym = s1->accessing_symbol;

	/* Shifts are solid, gotos are dashed, and error is dotted.  */
	char const *style =
	  (TRANSITION_IS_ERROR (trans, i) ? "dotted"
	   : TRANSITION_IS_SHIFT (trans, i) ? "solid"
	   : "dashed");

	if (TRANSITION_IS_ERROR (trans, i)
	    && strcmp (symbols[sym]->tag, "error") != 0)
	  abort ();
	output_edge (s->number, s1->number,
		     TRANSITION_IS_ERROR (trans, i) ? NULL : symbols[sym]->tag,
		     style, fgraph);
      }
}


/*-------------------------------------------------------------.
| Output in FGRAPH the current node specifications and exiting |
| edges.                                                       |
`-------------------------------------------------------------*/

static void
print_state (state *s, FILE *fgraph)
{
  struct obstack node_obstack;

  /* A node's label contains its items.  */
  obstack_init (&node_obstack);
  print_core (&node_obstack, s);
  obstack_1grow (&node_obstack, '\0');
  output_node (s->number, obstack_finish (&node_obstack), fgraph);
  obstack_free (&node_obstack, 0);

  /* Output the edges.  */
  print_actions (s, fgraph);
}


void
print_graph (void)
{
  state_number i;
  FILE *fgraph = xfopen (spec_graph_file, "w");
  start_graph (fgraph);

  /* Output nodes and edges. */
  new_closure (nritems);
  for (i = 0; i < nstates; i++)
    print_state (states[i], fgraph);
  free_closure ();

  finish_graph (fgraph);
  xfclose (fgraph);
}